Hoses, for example hydraulic and pneumatic hoses, conventionally comprise a flexible inner tube, such as a rubber or plastic inner tube surrounded by one or more tubular braids of metal wires.
Since these hoses are used for conveying high pressure fluids or gases, they have to withstand the forces of the pressure within the hose. In order to obtain a high impulse strength, high strength carbon steel wires are utilized as reinforcing elements.
In a still continuing effort to save weight of a hose reinforcement and to increase the flexibility, there is a trend to use wires with a higher tensile strength.
However, because of the high internal pressure, high transversal stresses are applied on the reinforcing elements. This has as consequence that the hose can not be utilized at its full strength.
To minimize the stresses on the wires, the strips can be braided in such a way that the braided structure does not provide 100% coverage of the inner tube but for example only 80 or 85% coverage. The separation between adjacent strips permits some freedom of movement of the wires during flexing and/or application of fluid pressure to the hose and results in good stress transfer from wire to wire.
Other ways to minimize the stresses applied on the wires is to provide a hose reinforcement which comprises several superimposed layers of wires. Such reinforcement structures, however, have the disadvantage of a higher weight.